Heat shrinkable film is made by making a stretchable film that when heated can be stretched and cooled in the extended state. When reheated the stretched film has a memory and will shrink back to its original state. In the manufacture of bubble wrap two stacked sheets of clear plastic film are used. One layer of the film is wrapped around a drum with holes punched in it, and suction is applied drawing one web of film into the holes that form the bubbles. The second layer of film acts as a cover because it is then laminated over the first so that when the two films are joined, they stick together and trap the air in the bubbles. During this process the films are heated and stretched. If a heat shrinkable film is used for at least the cover the bubble wrap will shrink.
Because it is attached to the film that houses the bubbles the film cannot shrink back under heat to its original size. However the shrinkage is sufficient to allow the bubble wrap to conform to an article such as a bundle of bottles but not enough to keep the bottles very tightly together. The bubble wrapped bottles need to be wrap with a conventional heat shrink film and heat shrunk to achieve the desired stability. For some applications where the article is like a cigar box where containers are not needed to be held tightly together a heat shrink bubble wrap film without a conventional heat shrink film wrap will suffice. The term article is being used to cover a unitary product or a bundle of products such as containers or bottles.